Metal Reclamation from Spent Lithium-Ion Battery Cathode Materials: Directional Conversion of Metals Based on Hydrogen Reduction

Abstract

The vast amount of spent lithium-ion batteries (LIBs), after exhausting their useful life, necessitates comprehensive recycling for metal reclamation. This paper proposed using hydrogen as a green reductant to reduce the cathode materials of spent LIBs, followed by wet magnetic separation. The inspiration behind this is to realize pollution-free and highly efficient separation of high-value metals from LIB cathode materials by utilizing hydrogen reduction to attain directional conversion of metals based on water solubility and magnetism differences. The effect of two major variables, that is, reduction temperature and time, on the leaching efficiency of Li and recovery of Ni, Co, and Mn, are investigated. The experimental results showed that the nickel–cobalt–manganese LIB cathode was primarily transformed into water-soluble Li2O, magnetic Ni–Co alloy, and nonmagnetic manganese oxides after hydrogen reduction under optimum conditions of 800 °C for 90 min. The reduction products underwent water-leaching to recover Li with a recovery of 96.8 wt %. Ni and Co are further separated magnetically from manganese oxides with recovery rates of 99.8 wt % Ni, 99.4 wt % Co into the magnetic fraction, and 90.3 wt % Mn into the nonmagnetic fraction.

Towards a low carbon process for lithium recovery from spent lithium-ion batteries by a carbon conversion control strategy of carbothermic reduction

“…For each batch of activation experiments, specific proportions of the cathode material and spent graphite, and zirconia balls (3 mm diameter) were placed in the zirconia pot. The effects on the Li leaching efficiency of the cathode materials to spent graphite mass ratios (6,12,18,24,30,36,42, and 48 g g −1 ), ball-to-powder mass ratios (5,10,15,20, and 25 g g −1 ), mill rotation speeds (200, 400, 600, and 800 rpm), and rotation times (2, 4, 6, and 8 h) were investigated systematically. To prevent the equipment from overheating, the ball mill was operated continuously for 10 min with 10 min intervals.…”

“…13 However, lithium is generally the last metal recovered through this method, resulting in a serious loss of lithium resources 14 and impurity of the extracted metal salts. In contrast, pyrometallurgical recovery of lithium-ion batteries, which primarily consists of reduction roasting [15][16][17] and molten-salt roasting, [18][19][20][21] mostly converts the LIBs into transition metal oxides and lithium salts that are readily separated. However, the agents used for molten-salt roasting contain sulphur, chlorine, or nitrogen, which produce hazardous gases and waste liquids, 22 and increase the load on subsequent processing.…”

Selective Lithium Extraction and Recycling of High-Value Metals from Spent LiNixCoyMn1–x–yO2 Cathode Materials

“…To reduce energy consumption and increase metal recovery efficiency, some processes combining pyrometallurgy and hydrometallurgy have been widely explored for recycling spent LIBs. − Yang et al reported a low-temperature chlorination pyrolysis technology for recycling spent NCM batteries. Similarly, (NH 4 ) 2 SO 4 has also been widely employed in the study of recycling spent LIBs.…”

The critical role of H2 reduction roasting for enhancing the recycling of spent Li-ion battery cathodes in the subsequent neutral water electrolysis

“…24 Gaseous reductants including NH 3 , 25 CH 4 , 26 and H 2 (ref. 27 and 28) have also been explored, and the results were promising in reducing the waste LIB cathodes.…”